Conventionally, electronic devices, such as personal computers, mobile telephones, personal digital assistants (PDAs), digital cameras, video cameras, music players, game machines, and vehicle navigation devices, include card connectors so as to use various types of memory cards, such as subscriber identity module (SIM) cards, multi-media cards (MMCs)(R), secure digital(SD) (R) cards, mini SD (R) cards, xD-picture cards (R), memory sticks (R), and smart media (R).
From the standpoint of usability, recent card connectors generally have a push/push structure that allows an operator to push a memory card into the card connector when inserting the memory card or even when removing it. Further, such card connectors are equipped with a detection switch that detects that a memory card has been inserted (see, for example, Japanese Patent Application Laid-Open (kokai) No. 2002-252045). There are generally two types of detection switches, the initial ON-type, where the contact points are in a contact state prior to insertion of the memory card and when the memory card is inserted, the contact points enter a non-contact state; and the initial OFF-type, where the contact points are in a non-contact state prior to insertion of the memory card and when the memory card is inserted, the contact points enter a contact state. Further, these detection switches can be classified into a rearmost-wall-placement-type for placement at the innermost or rearmost wall of the card connector, and a side-wall-placement-type for placement at a side wall of the card connector.
FIG. 7 is a view showing a conventional card connector provided with an initial ON-type detection switch disposed at the rearmost wall.
In the drawing, reference numeral 301 denotes a memory card that is inserted into the card connector. An arrow denoted by 303 indicates the direction of insertion and removal of the memory card 301. Further, reference numeral 304 denotes a first contact member of the detection switch and is fixed to an insulating housing 302 of the card connector. In the state shown in the drawing, an insertion end 306 of the memory card 301 presses and moves an engagement portion of the second contact member 305 of the detection switch toward the rear, so that the contact point 307 of the second contact member 305 separates from the contact point 309 of the first contact member 304. For this reason, the contact points of the detection switch are in a non-contact state. Due to this, the fact that the memory card 301 has been inserted is detected.
Nonetheless, with the above-described conventional card connector, the non-contact state of the contact points of the detection switch is maintained during insertion of the memory card 301. Accordingly, it is easier for dust to adhere to the contact points, thus increasing the chances of contact failure occurring when the memory card 301 is removed. Further, the amount of displacement of the second contact member 305 when the memory card 301 is removed is small, and further, the contact pressure applied to the contact point 309 of the first contact member 304 by the engagement portion of the second contact member 305 cannot be increased. Accordingly, the amount of wiping performed between the engagement portion of the second contact member 305 and the contact point 309 of the first contact member 304 becomes extremely small, whereby a cleaning effect for the contact points by means of wiping cannot be expected. Furthermore, when the memory card 301 is inserted, the insertion end 306 pushes and moves the second contact member 305 toward the rear, so the reactive force of a spring which supports the second contact member 305 is applied in a direction to push and return the memory card 301. Therefore, in a state where the memory card 310 is loaded in the card connector, the points of contact between the terminals of the memory card 301 and the terminals of the card connector may shift. Another problem exists in that since the size of the card connector in the thickness direction is limited, it is necessary to dispose mounting leads at the rear of the card connector. For this reason, the fixing portions of the mounting leads are disposed at the rearmost wall, thus making the structure of this wall complicated.
Further, in the case of a card connector provided with an initial OFF-type detection switch disposed at the rearmost wall, the amount of wiping can be increased by lengthening the spring that supports the contact member of the detection switch, and a cleaning effect for the connection points of the detection switch by means of wiping can be expected. Nonetheless, since a certain degree of space becomes necessary at the rear of the card connector, the card connector cannot be made compact. Furthermore, since the spring is long, the over-stroke in the push/push structure cannot be shortened. Also, if attempts are made to make the card connector more compact, it is necessary to decrease the distance between the contact points (i.e., the contact gap) of the detection switch, thus making assembly of the card connector difficult. Further, as in the case of a card connector provided with an initial ON-type detection switch disposed at the rearmost wall, when the memory card is inserted, the insertion end pushes and moves the contact member of the detection switch toward the rear. Accordingly, the reactive force of the spring supporting the contact member is applied in a direction to push and return the memory card. For this reason, in a state where the memory card is loaded in the card connector, the points of contact between the terminals of the memory card and the terminals of the card connector may shift. Another problem exists in that since the size of the card connector in the thickness direction is limited, it is necessary to dispose mounting leads at the rear of the card connector. For this reason, the fixing portions of the mounting leads are also disposed at the rearmost wall, so the structure of this wall becomes complicated.
Further, in the case of a card connector provided with an initial ON-type detection switch disposed at the side wall, since it is an initial ON-type switch, it is necessary to increase the contact pressure at the initial state in order to improve the contact reliability of the contact points of the detection switch. However, when each of the members is formed to be thin in order to make the card connector more compact, at the time of solder re-flow, the entire card connector may deform because of residual stress stemming from the contact pressure at the initial state. Furthermore, since the contact points of the detection switch are maintained in a non-contact state during insertion of the memory card, it becomes easier for dust to adhere to the contact points, thus increasing the chances of contact failure occurring when the memory card is removed. Further, the amount of displacement of the contact member of the detection switch when the memory card is removed is small, and the contact pressure cannot be increased. Accordingly, the amount of wiping performed becomes extremely small, whereby a cleaning effect for the contact points of the detection switch by means of wiping cannot be expected.
Further, in the case of a card connector provided with an initial OFF-type detection switch disposed at the side wall, the amount of wiping can be increased by lengthening the spring that supports the contact member of the detection switch, and a cleaning effect for the connection points of the detection switch by means of wiping can be expected. Nonetheless, since a certain degree of space is needed from the side to the rear of the card connector, it becomes impossible to make the card connector more compact. Also, the form of the spring becomes complicated. Furthermore, when the position of the side surface of the memory card displaces from the designed position inside the card connector, the contact pressure of the contact points of the detection switch and the amount of wiping change, so the reliability of the detection switch deteriorates. That is, since the width of the card slot of the card connector is set to be larger than the width of the memory card, a gap exists in the widthwise direction between the wall surface of the card slot and the memory card. Therefore, in a state where the memory card is loaded in the card connector, the memory card may tilt. Should this occur, the side surface of the memory card displaces from its intended or designed position. Further, the same is true when variations occur in the width of the memory card during manufacture, so similarly, the side surface of the memory card displaces from its designed position. Due to this, the contact pressure of the contact points of the detection switch and the amount of wiping change greatly, whereby the reliability of the detection switch deteriorates. It is also necessary to lengthen the spring that supports the contact member of the detection switch so as to cope with the position displacement of the side surface of the memory card. In this case, since a certain amount of space from the side to the rear of the card connector becomes necessary, the card connector cannot be made to be more compact. Also, when the spring is strengthened in order to increase the contact pressure of the contact points, friction with the side surface of the memory card increases, whereby ejection of the memory card with a push/push structure becomes difficult.